NC-2009 SSc8: Light Pollution Reduction

  • NC CS- SSc8 Light Pollution Reduction- Credit Requirements
  • Interior and exterior lighting

    Addressing both interior and exterior lighting, this credit seeks to reduce light pollution that can block our view of the night sky and cause human health problems as well as ecological problems for many birds, insects, and other animals. Light pollution often represents nighttime lighting that isn’t needed, wasting energy while causing light trespass and contrast, reducing visibility.

    SSc8 YouTube video

    Better lighting = Better safety, less energy

    Many people think that more lighting means better nighttime safety and security. However, too much exterior lighting can make outdoor and parking areas less safe by creating high contrast between lit and unlit spaces. Among other problems, when the human eye is flooded by bright light, it becomes harder to adjust to darker areas and shadows. Too much exterior lighting also means unnecessary energy consumption. Some objectives to keep in mind when striving for safe, efficient, and aesthetically pleasing lighting design are lighting uniformity, low contrast, no glare, and preventing light from spilling off the site. This can be achieved through judicious selection of fixtures with full cutoffA full cutoff luminaire has zero candela intensity at an angle of 90 degrees above the vertical axis (nadir or straight down) and at all angles greater than 90 degrees from straight down. Additionally, the candela per 1,000 lamp lumens does not numerically exceed 100 (10%) at an angle of 80 degrees above nadir. This applies to all lateral angles around the luminaire. that direct light toward the ground but prevent it from shining up into the night sky.

    Full-cutoff luminaires reduce light pollution, improving views of the night sky.

    The four requirements can make it complicated

    This credit has four separate requirements, which can make compliance complicated—though not necessarily difficult. One addresses indoor lighting spilling to the outdoors, and three deal with exterior lighting, including façade lighting, site lighting of areas like pathways and parking lots. In most circumstances, these requirements are relatively easy and cost-neutral to meet. The biggest challenge often comes in dealing with light-trespass limits—light bleeding off the project site into a neighboring site—on projects with small or constrained sites. You will also need to attain low lighting power densities per ASHRAE 90.1-2007, which is a good general practice and won’t require you to compromise on aesthetics or cost.

    LEED boundary is important

    You’ll need to pay careful attention to establishing a LEED project boundary, which plays an important part in meeting light trespass requirements. Involve an exterior lighting designer (or landscape architect) early in the design process to develop photometric plans and guide fixture selection during design.

    FAQs for SSc8

    Are residential spaces exempt from the interior lighting calculations?

    Yes, as of 4/1/12 per LEED for Homes 2008 Interpretation #10147, “residential spaces (dwelling units only) within the scope of other LEED projects are also exempt from the interior lighting requirements.”

    Do existing fixtures need to be included in the exterior lighting calculations?

    Yes, if they are within the LEED project boundary.

    Can the Application Guide for Multiple Buildings and On-Campus Building Projects be used for the exterior lighting requirements?

    Yes, as long as the entire site meets the requirements.

    Can a mix of Option 1 (opaque surfaces) and Option 2 (automatic controls) be used to meet the interior lighting requirements?

    Yes.

    Are hospitals exempt from interior lighting requirements?

    No, hospitals are not exempt from the interior lighting requirements.

    What effect did the November 2011 ASHRAE table 9.4.6 Addendum i have on exterior lighting power allowances?

    Significant reductions for tradable surfaces in LZ1 and LZ2 and some in LZ3. See the new table for details. It also added lighting power allowances according to light zones, removed a 5% adder, and introduced a base site allowance. Suggest revising response and adding a link to the Addendum i available for free download on ASHRAE website.

    What about zero lot line projects, where is the boundary?

    You can use the curb line.

    To calculate building façade lighting power density, how do you determine the area used in the calculation?

    Use only the area that has measurable light on the surface; baseline and proposed are the same.

    Where are vertical footcandles measured at the site boundary?

    At grade level.

    Is signage included in the LPD calculations for building façades?

    No, per ASHRAE table 9.4.5, you can exclude lights in display windows, advertising, and directional signs as long as they are switched separately from other lighting.

    Does uplight that is under a canopy count towards the limitation of total initial design fixture lumens at 90 degrees or higher from nadir?

    If the canopy blocks 100% of the light then yes, but this is unlikely. Any light spillage needs to be counted toward the uplighting limit, but calculating this can be difficult. Using downlights is recommended instead.

    Is flag lighting exempt from this credit?

    Not currently, but USGBC is looking at exempting flag lighting from LEED v4 requirements.

    Are city-owned lights within a project's property required to comply with credit requirements?

    According to LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10236, street lighting that is required by the governmental authorities to be installed within the LEED project’s lighting boundary (whether existing or new) does not need to be included in any of the calculations.

    For campus projects, do all existing light fixtures need to comply with credit requirements at the time of a project's submittal?

    All existing fixtures within the LEED project boundary would need to comply with the SSc8 requirements at the time the project is submitted for review. However, if the project elected to use the campus property boundary as the "lighting boundary" for SSc8 as allowed by LEED Interpretation #10236, existing fixtures within the lighting boundary, but outside the specific LEED project boundary would not have to comply with any of the SSc8 requirements. Essentially, the "lighting boundary" is only used in such circumstances for evaluating that the light trespass requirements are met at that boundary by lighting located within the LEED project boundary.

    What advertising lights or signs must comply with credit requirements and which are exempt?

    Advertising and directional signage, as explained in Addendum i of ASHRAE 90.1-2007, and further defined in the Users Manual for ASHRAE 90.1-2007, is exempt.  Essentially, that means that internally illuminated advertising signs are exempt, but those illuminated by lighting that is not ‘integral’ to the signage itself must be included in the calculations.

Legend

  • Best Practices
  • Gotcha
  • Action Steps
  • Cost Tip

Pre-Design

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  • Designate one responsible party to oversee exterior lighting-related LEED credit requirements. For large projects, this person may be the civil engineer or landscape architect. For small projects it may be the architect, lighting designer, or other relevant team member.


  • Identify the building owner’s goals for occupant safety and comfort as well as for architectural lighting, including façade lighting. Include these goals in the Owners Project Requirements for EAp1: Fundamental Commissioning


  • One of the biggest barriers to reducing light pollution is the cultural and aesthetic affinity for brightly lit buildings. Owners can play an important leadership role in contending with these expectations, establishing aesthetic goals that do not include excess lighting for purely aesthetic purposes. The design team can play an important role by maintaining low levels of lighting and highlighting specific façade architectural features with focused, low intensity lights.


  • Projects that demand brightly lit facades and entrances, such as casinos, hotels, theatres and commercial complexes, may have a hard time reconciling these desires with the requirements of this credit. Deliberate lighting design can forge a compromise between the desire to emphasize the building facades and the need to eliminate light pollution in order to meet the credit requirements.


  • Identify the urban lighting zone as defined by IESNA RP-33, based on the population density of the neighborhood, in order to establish lighting requirements.


  • Finalize the LEED project boundary in coordination with other LEED credits. The responsible party and the project team should identify the lighting fixtures close to the boundary that will be part of the lighting trespass analysis.


  • Projects with a zero lot line may choose to use the curb as the LEED boundary for the purposes of documenting light trespass only, while using the site boundary for other credits. This is one of the few exceptions to the rule that the LEED boundary and corresponding site area be consistent across multiple credits. Sites that abut public rights of way may similarly use the curb to establish the site boundary for the purposes of LEED documentation. It can be challenging for projects with zero lot lines or with little open space to meet the maximum exterior illuminance requirement of 0.1 footcandles at the site boundary. Project teams are only responsible for lights that are part of their project. For example, municipal lights about which the project has no control do not need to be considered. 


  • Campus projects can choose whether to comply with the requirements for the building site boundary or to meet the light trespass requirements for the campus as a whole. For a project on a campus, choosing to meet the light trespass requirements at the building level can be very difficult.


  • Identify local or regional lighting laws or required lighting levels for rights-of-way that may apply to the project site. These regulations may help teams identify areas to focus on when dealing with lighting trespass in the design.


  • Discuss fixture and lamp options with the landscape designer, civil engineer and other project team members, focusing on both reducing overall lighting power density, and on avoiding light trespass. Avoiding light fixtures that shine up into the sky is the easiest way to reduce light pollution and make better use of lighting. This can be done by eliminating exterior lighting entirely or by selecting “cut-off fixtures” with opaque covers that direct light downward.


  • Local or regional laws that regulate lighting levels typically do not require minimum input power in watts. Going beyond these local requirements by selecting energy-efficient fixtures can help your project meet codes for comfort and safety goals without compromising energy efficiency.


  • The credit requires a photometric study on site lighting that may add minor consultant costs but will add value by optimizing the design.


  • Optimizing lighting can eliminate unnecessary costs for extra lights and high-power fixtures.


  • Many smaller fixtures may make for a better layout than fewer high-wattage ones. The designer should be able to advise about additional infrastructure costs associated with an atypical lighting design. Low power density and light intensity may require higher first costs for fixtures that will save electricity costs during operations.


  • Rebates and incentives on the federal, state, and local levels are available for low-power and Energy Star lamps.


  • Safety concerns are not typically a valid excuse for higher exterior lighting allowances. Despite a perception of better safety with brighter lighting, floodlights can often create areas of deep shadow, and the high contrast can be difficult for the human eye to navigate. Use good design, downlights, and work with the owner to address any concerns.

Schematic Design

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  • Interior lighting


  • Be aware of all requirements for interior lights so that fixtures do not direct light through windows to the outdoors. Identify locations where fixtures might have a direct line of sight to a window or other opening. The lighting designer should either eliminate those fixtures from the design, provide shades to prevent more than 10% of light from shining outdoors, or include controls to reduce the input power by 50% between 11 p.m. and 5 a.m.


  • Interior lighting cannot spill out of the windows after business hours, defined as 11 p.m. – 5 a.m. in the credit requirements. Window coverings or automatic controls like timers, occupancy sensors, or master switches have to shut off or reduce the input power by 50% for all non-emergency indoor lights during that time.


  • Fixtures that throw 50% or more of the cone of light out a window are likely to present problems.


  • To avoid letting this credit slip through the cracks, project owners or architects should ask the lighting designers at the outset of the project how they plan to achieve each aspect of the credit.


  • Additional light controls and automatic window screens may add to construction costs, but controls can reduce electricity consumption.


  • Exterior lighting


  • Identify the project location and IESNA-designated zone to determine the threshold for exterior lighting levels.  Utilize resources like the website www.citydata.com to identify relevant population density and appropriate designation.


  • The lighting designer includes the design intent in Basis of Design for EAp1: Fundamental Commissioning, for all outside lighting requirements, listing minimum illuminance in footcandles, lumens, or candela for all spaces with controls, fixture requirements and design approach.


  • The lighting designer then develops the exterior lighting layout and selects fixtures that optimize light with low power use.


  • Nadir illustratedTo determine the total power density for the project, the lighting designer tabulates all exterior space and identifies the wattage of selected fixtures to compare it with the LPD allowable by ASHRAE 90.1-2004, Exterior Lighting Section. The selected fixtures should have full shielding or cutoff to reduce light directed toward the night sky.


  • The lighting designer develops a photometric study for exterior lighting intensity, the impact of shades and cutoff fixtures, and light trespass from the project boundary. Use the photometric study to inform any changes in the design.


  • The key to achieving this credit is to find the optimum balance between lighting quality and lighting energy consumption. It is often assumed that more light is better, but a low level of uniform lighting throughout a site will eliminate the need to install bright halogen lamps that illuminate some areas and leave others dark in contrast.


  • Exterior lighting includes all ground lighting, all façade lighting, flag lighting, any rooftop or terrace lighting, and any other fixtures outside the building. Pay careful attention to exterior light fixtures and light levels at building entrances close to the LEED site boundary.


  • Revisit the LPD calculations to make sure any design changes maintain the threshold limits.


  • ASHRAE’s exterior lighting density table lists exterior spaces under two categories. Tradable surfaces are those where the average LPD of all those surfaces are within the total LPD limits. For example, in LZ4, both sales canopy lighting and stairway lighting have a maximum of 1.0 Watts/ft2. The project may decide to increase sales canopy lighting to 1.1 Watts/ft2 as long as the stairways compensate with a decreased LPD of 0.9 Watts/ft2 (given that the surfaces are the same area) so that the average of the two is 1.0 Watts/ft2. For non-tradable surfaces, such as bank ATMs, each space must individually comply with the ASHRAE requirements. Identify whether exterior surfaces are tradable in order to provide flexibility.


  • A photometric study will facilitate communication about lighting levels among the designer, owner and the design team. The study entails computer modeling simulating the lighting intensity of the designed layout in footcandles, lux or candela. It allows the designer to see the resulting output, with iterative design options as the fixtures are reduced or replaced. Typically the photometric study measures light levels in a 10’x10’ grid. The analysis also investigates the maximum initial illuminance value at horizontal and vertical limits on the site boundary to ensure they are within the limits of the project zone. If you find that lights are above the threshold, the designer may want to explore alternative numbers of fixtures and fixture types and present these alternatives to the owner, who makes the final decision.


  • Avoid aiming light at highly reflective site and ground surfaces, such as white pavement and water features, which can exacerbate light pollution. The photometric study may not capture these characteristics.


  • Some lighting manufacturers will offer to perform a photometric study of your site if your team selects their product for the project.


  • Security-oriented lighting designs such as those for prisons, parking lots, and walkways often focus too much on big, bright lamps. This can be counterproductive, creating high contrast between lit and unlit spaces, worsening visibility in both places. Use more moderate, uniform light levels for improved designs.


  • Some types of lighting are exempt from the ASHRAE limits on power density. Examples include advertisement signage, transportation signage, athletic fields, storage, and historic landmarks and other public monuments. Refer to Exceptions under ASHRAE 90.1 2004 Section 9.4.5.


  • The lighting intensity of conventional fixtures such as halogens, incandescents, and sodium halide lighting, drops off significantly after the first year of operation. LED or fluorescent fixtures will better maintain their lighting intensity at the level of the installation—contrary to the common perception that low power wattage fixtures, such as LEDs or fluorescents, have low lighting intensities.


  • Full cutoff fixtures can generally be specified at zero cost premium.


  • Cost premiums for this credit may come from the higher number of (shorter) poles and fixtures needed to achieve greater lighting uniformity.


  • New fixtures like LEDs with high lighting levels but low power density may cost more than conventional halogen fixtures, but most of the new fixtures have longer life and are less expensive to operate due to low electricity use and infrequent lamp replacement.


  • Costs for the photometric study can be decreased if manufactures agree to do their own calculations, which is common if you select their fixtures.

Design Development

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  • Come to an agreement among the owner, landscape designer and lighting designer about the appropriate lighting levels and site lighting distribution.


  • Demonstrate to the owner the project team’s decision about lighting levels for the final design. Owners may need to be shown similarly lit areas to understand the implications of a shift from a brightly lit façade and terrace.


  • Locally mandated lighting levels for exterior fixtures higher than LEED-mandated ASHRAE levels have been a stumbling block for credit compliance, but with proper documentation supported by a clear narrative, this challenge can be overcome. There is an option to not include those fixtures in the LPD calculations and light trespass requirement, but you must demonstrate that these fixtures are full cutoff. To document the credit, make the case that the legally mandated fixtures are beyond the control of the project. Demonstrate that the project has met the requirements with rest of the lighting. Provide a detailed photometric plan, the municipal regulations, and a narrative describing how the project has achieved all requirements of the credit except where the municipal regulations overrule it.

Construction Documents

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  • Confirm all the lighting fixtures are listed on the lighting plan. This ensures that the correct components are purchased and installed to maintain the credit requirements.


  • The designer reviews the final bid documents and budget estimates to confirm that the fixtures have not been substituted for by another type, and that interior lighting controls and window shades are not omitted. 


  • If your team undertakes a value engineering process, make sure the full cutoff fixtures are not eliminated from the list or replaced by incandescent or high-powered halogen fixtures. These changes are often overlooked and may cost the project this credit.


  • If the project is going for multi-party contractor bid, make sure the bid’s package reflects the fixture specifications and performance. Otherwise the contractor may replace the specification with a similar lower-cost fixture that doesn’t have the same wattage or a cover for cutoff.


  • Full-cutoff luminaires should not cost more than conventional fixtures, but other common strategies for meeting this credit may add costs. These include controls, timers, sensors, and  low-power lights like LEDs. Ensure that these features are not eliminated during value-engineering.       

Construction

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  • The designer should review shop drawings and visit the site for installation inspection. This ensures that the fixtures have a cut-off for uplighting, the ballasts are as specified, and the controls are all included.


  • The commissioning agent carries out the functional testing for all control sequences and timers if installed for lighting design.

Operations & Maintenance

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  • Timer controls and automatic switches should be commissioned and inspected for performance periodically throughout their life to ensure they continue to serve the intent of the credit requirements.


  • The facility manager should be involved in the decision of whether to select light timers or automated blinds to comply with interior lighting requirements. Both solutions offer opportunities and challenges during building use, depending on how the building is used and occupied.


  • Long-life, low-power lamps like fluorescents and LEDs will help keep costs low for operations and maintenance.

  • USGBC

    Excerpted from LEED 2009 for New Construction and Major Renovations

    SS Credit 8: Light pollution reduction

    1 Point

    Intent

    To minimize light trespass from the building and site, reduce sky-glow to increase night sky access, improve nighttime visibility through glare reduction and reduce development impact from lighting on nocturnal environments.

    Requirements

    Project teams must comply with one of the two options for interior lighting AND the requirement for exterior lighting.

    For interior lighting

    Option 1

    Reduce the input power (by automatic device) of all nonemergency interior luminaires with a direct line of sight to any openings in the envelope (translucent or transparent) by at least 50% between 11 p.m. and 5 a.m. After-hours override may be provided by a manual or occupant-sensing device provided the override lasts no more than 30 minutes.

    OR

    Option 2

    All openings in the envelope (translucent or transparent) with a direct line of sight to any nonemergency luminaires must have shieldingShielding is a nontechnical term that describes devices or techniques that are used as part of a luminaire or lamp to limit glare, light trespass, or sky glow. (controlled/closed by automatic device for a resultant transmittance of less than 10% between 11 p.m. and 5 a.m.).

    For exterior lighting

    Light areas only as required for safety and comfort. Exterior lighting power densities shall not exceed those specified in ANSI/ASHRAE/IESNA Standard 90.1-2007 with Addenda i for the documented lighting zone. Justification shall be provided for the selected lighting zone. Lighting controls for all exterior lighting shall comply with section 9.4.1.3 of ANSI/ASHRAE/IESNA Standard 90.1- 2007, without amendments1.

    Classify the project under 1 of the following zones, as defined in IESNA RP-33, and follow all the requirements for that zone:

    LZ1: Dark (developed areas within national parks, state parks, forest land and rural areas)

    Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.01 horizontal and vertical footcandlesVertical footcandles occur on a vertical surface. They can be added together arithmetically when more than 1 source provides light to the same surface. (0.1 horizontal and vertical luxMeasurement of lumens per square meter.) at the LEED project boundary and beyond. Document that 0% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).

    LZ2: Low (primarily residential zones, neighborhood business districts, light industrial areas with limited nighttime use and residential mixed-use areas)

    Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.10 horizontal and vertical footcandles (1.0 horizontal and vertical lux) at the LEED project boundary and no greater than 0.01 horizontal footcandlesHorizontal footcandles occur on a horizontal surface. They can be added together arithmetically when more than 1 source provides light to the same surface. (0.1 horizontal lux) 10 feet (3 meters) beyond the LEED project boundary. Document that no more than 2% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).

    LZ3: Medium (all other areas not included in LZ1, LZ2 or LZ4, such as commercial/ industrial, and high-density residential)

    Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.20 horizontal and vertical footcandles (2.0 horizontal and vertical lux) at the LEED project boundary and no greater than 0.01 horizontal footcandles (0.1 horizontal lux) 15 feet (4.5 meters) beyond the site. Document that no more than 5% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).

    LZ4: High2 (high-activity commercial districts in major metropolitan areas)

    Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.60 horizontal and vertical footcandles (6.5 horizontal and vertical lux) at the LEED project boundary and no greater than 0.01 horizontal footcandles (0.1 horizontal lux) 15 feet (4.5 meters) beyond the site. Document that no more than 10% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).

    LZ2, LZ3 and LZ4 - For LEED project boundaries that abut public rights-of-way, light trespass requirements may be met relative to the curb line instead of the LEED project boundary.

    For all zones

    Illuminance generated from a single luminaire placed at the intersection of a private vehicular driveway and public roadway accessing the site is allowed to use the centerline of the public roadway as the LEED project boundary for a length of 2 times the driveway width centered at the centerline of the driveway.

    1The requirement to use ASHRAE Addenda is unique to this credit and does not obligate Project teams to use ASHRAE approved addenda for other credits.
    2 To be LZ4, the area must be so designated by an organizations with local jurisdiction, such as the local zoning authority.

    Credit substitution available

    You may use the LEED v4 version of this credit on v2009 projects. For more information check out this article.

    Potential Technologies & Strategies

    Adopt site lighting criteria to maintain safe light levels while avoiding off-site lighting and night sky pollution. Minimize site lighting where possible, and use computer software to model the site lighting. Technologies to reduce light pollution include full cutoff luminaires, low-reflectance surfaces and low-angle spotlights.

Organizations

Illuminating Engineering Society of North America

This organization provides general exterior lighting design guidance.


International Dark-Sky Association IDA

Links to manufacturers with IDA-approved fixtures, information sheets and practical guides, and resources for learning.


Lighting Research Center

This website is associated with the Lighting Research Center at Rensselaer Polytechnic.

Software Tools

SUPERLITE 2.0 ( Lawrence Berkeley National Laboratory)

SUPERLITE 2.0 is a lighting analysis program designed to accurately predict interior illuminance in complex building spaces due to daylight and electric lighting systems.


Litescape 3.0 (Standard Performance Evalutation Corporation)

Lighting simulation software.


Visual 3D

For someone who does not design lighting as their primary service, this free lighting calculation software can be downloaded here.

Other

Elights (Dark-Sky Lighting Products)

Elights sells full cut-off light fixtures.

Technical Guides

Lighting Power Density

A comprehensive source for understanding the lighting models underlying the commercial lighting power limits developed in ASHRAE/IESNA 90.1-2004.


Outdoor Site-Lighting Performance: A Comprehensive and Quantitative Framework for Assessing Light Pollution

This paper describes a method of measuring and predicting glow, glare and trespass in outdoor lighting.


Lighting for Exterior Environments

This publication from the Illuminating Engineering Society defines urban lighting zones according to population density.

Exterior Lighting Power Density

All Options

Perform calculations to demonstrate credit-compliance with exterior lighting power density requirements.

Compliant Light Fixtures

Refer to manufacturer cut sheets for the angle of light spilling above horizontal, the candela graph for maximum candela notation, and watts.

Intersection of Driveway and Roadway

This graphic illustrates SSc8's particular rule for how the site boundary relative to illuminance can expand when a driveway meets a public roadway.

Luminaire Schedule

The schedule lists all the exterior fixtures that will be accounted for in the the lighting power density calculations required for this credit.

Exterior Lighting Layout

Provide documentation like this example to showcase the exterior lighting layout plan. You'll refer to this plan in providing fixture and photometric analysis.

Annotated Photometric Plans

This set of annoatated photometric plans was created by Bill Swanson, P.E. for LEEDuser as a teaching tool for SSc8 documentation issues. They are not intended as examples of actual documentation, though a lot can be learned from them. These documents include a detailed plan showing a compliant site with light levels in the site and as required around the boundary, with advice and useful tips. The fixture comparison document is a means to better understand and compare the spill light from different light fixtures and placements. Think of the purple line as the edge of a cutout with a pin thru the paper where the pole is.  Move the cutout over the site when locating poles, if the cutout overlaps the line beyond the property line then that fixture cannot be located and aimed as placed. The driveway entrance example shows the impact of fixture placement around driveway entrances, and the special allowance for the site boundary around those entrances.

LEED Online Forms: NC-2009 SS

The following links take you to the public, informational versions of the dynamic LEED Online forms for each NC-2009 SS credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.

Version 4 forms: (newest)

Version 3 forms:

These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions on these forms; for more information, visit LEED Online and click "Sample Forms Download."

Design Submittal

PencilDocumentation for this credit can be part of a Design Phase submittal.

539 Comments

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David Hubka Director - Operations Transwestern Sustainability Services
Aug 11 2014
LEEDuser Expert
762 Thumbs Up

Search Light at Prison

Would a prison search light be exempt from the credit requirements?

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners Aug 11 2014 Guest 1395 Thumbs Up

It would not be specifically exempt but I think you could claim a special circumstance. It is certainly in line with other types of lighting that are exempted. i think it would be important to state that the light is only used under emergency situations (assuming this is true). I must say though, I'm having a hard time getting my head around the idea of prison exterior lighting ever being able to meet the credit requirements.

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David Hubka Director - Operations, Transwestern Sustainability Services Aug 11 2014 LEEDuser Expert 762 Thumbs Up

Thanks for the response Glenn, and i would agree that it lines up with the other types of lighting that are exempted.

The project is not a prison, I asked the question in this manner to help illustrate the way the specific light fixture would be used. This project building is in a remote location of the world and the light is used to make sure animal(s) are not in the area so that occupants are safe/secure when they leave the facility. It will only be used during an emergency event.

thanks for the quick response.

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Bill Swanson PE, LEED AP, Integrated Architecture Aug 11 2014 LEEDuser Expert 14731 Thumbs Up

I have not heard of them allowing any exceptions for security related lights. Even if they are rarely turned on they must meet the credit requirements.

ID#5192 made on 05/06/2009
Prerequisite/Credit: SSc8 - Light pollution reduction
Rating System: LEED BD+C: New Construction, LEED BD+C: Schools, LEED BD+C: Core and Shell Rating System Version: v2 - LEED 2.2, v3 - LEED 2009, v2 - Schools 2007

Inquiry
Our project is an office building located in an area surrounded mostly by residential properties. The office building and site will comply with the Light Pollution Reduction credit. The firm that will occupy this office building works on many projects of a sensitive nature so security is a significant concern, both for employees arriving early or working after dark and for protection of the facility from intrusion. Is it acceptable to include motion-sensor activated lights that do not fall within the allowable site lighting wattage? These lights would be located in the immediate vicinity of the building and would only be enabled to turn on when other site lights are off. They would only remain on for a limited time following activation. If such motion-sensor activated lights are allowed, can they be excluded from the other requirements of this credit, property line illuminance and uplight components, since their purpose is only safety and security?

Ruling
The applicant is requesting confirmation if it is acceptable to exceed the lighting power density requirements with motion responsive after hours security lighting that is only enabled when the other site lighting is off. Based on the description provided, this strategy is only acceptable provided that when the security lighting is ON, the combined security and general lighting that remains ON, does not exceed the lighting power density thresholds and the security lighting is capable of being controlled to prevent simultaneous operation with the offsetting exterior luminaires. The second question asks if the lights can be excluded from the other requirements of SSc8 and the answer is no. These luminaires must meet the light trespass requirements relative to their declared environmental zone at the applicable site boundary, as well as the sky glowSky glow is caused by stray light from unshielded light sources and light reflecting off surfaces that then enter the atmosphere and illuminate and reflect off dust, debris, and water vapor. Sky glow can substantially limit observation of the night sky, compromise astronomical research, and adversely affect nocturnal environments. requirements of the credit. Applicable Internationally.

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David Hubka Director - Operations, Transwestern Sustainability Services Aug 11 2014 LEEDuser Expert 762 Thumbs Up

thanks for the response Bill and for tracking down this info.

Post a Reply
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LEED Consultant Green Building and Alternative Energy
Jun 24 2014
LEEDuser Member
1301 Thumbs Up

Building operating 24 hours

Hello,

We are working on a project which is an industrial facility that will operate 24 hours, for the interior lighting in the offices area we will reduce the input power, in the manufacturing area the night shift will only operate 2 of 6 lines, the illumination in these 2 lines will be the only ones that will be working during the night and the other 4 lines will be programmed to be turned off, this represents about a 60% of reduction in the interior lighting, can this be acceptable as a reduction in the interior lighting?

Thank you in advance!

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 25 2014 LEEDuser Expert 14731 Thumbs Up

If business picks up will they operate 4 of the 6 lines?

Technically the wording of the credit says that every light that shines directly outside must have power reduced by 50% at night. You may find a sympathetic reviewer that will let you reduce the power in the room by more than 50%. But the controls need to be automatic and not reliant on someone flipping a switch.

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LEED Consultant Green Building and Alternative Energy Jun 30 2014 LEEDuser Member 1301 Thumbs Up

Thank you for your answer Bill, we will try to submit the credit via reducing the input power more than 50% in the room, as you commented.

I will let you know if this criteria was accepted.

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LEED Consultant Green Building and Alternative Energy
Jun 24 2014
LEEDuser Member
1301 Thumbs Up

Temporary lighting fixtures

Hello,

We are working on a project that in a future includes an addition, the LEED boundary for the current project is just in the limit between the 1st building and the addition, for this 1st building there are some wall packs just in the LEED boundary that will not comply with the lighting trespass requirements, but these wall packs are temporary because they will be eliminated when the addition will be completed. Should we include these temporary wall packs in the calculation?

Also, I would like to confirm that we can apply for this credit following the LEED v4 requirements that only considers exterior lighting requirements, because the building will be used 24 hrs.

Thank you in advance!

Thank you in advance.

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 25 2014 LEEDuser Expert 14731 Thumbs Up

http://www.usgbc.org/articles/use-v4-credits-your-v2009-project
These are the rules for using a v4 version of the credit.

Any light fixtures that are installed in this phase of work need to be considered. Some times the most permanent work was originally intended as temporary. How many projects in 2008 got put on hold indefinitely when the global economy tanked. The future is uncertain so measure the present scope of work. If these wall packs are a problem try selecting something else that is compliant.

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners Jun 25 2014 Guest 1395 Thumbs Up

Rosemaria,

You should definitely use the v4 version of this credit. It may also solve your wallpack problem. If the area where the addition will be is on the same piece of property as the project, or a piece of property owned by the same owner and the same or lower LZ designation, then your trespass calculations are made farther away than the LEED project Boundary. See the "Lighting Boundary" in the v4 credit.

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LEED Consultant Green Building and Alternative Energy Jun 30 2014 LEEDuser Member 1301 Thumbs Up

Thank you Bill and Glenn,

This will be my 1st time submitting one credit of the v4 version in a building looking for LEED NC version v2009, so I have some questions about it. I would just like to confirm that this credit in the v4 version does not include any requirement for the interior lighting, and also, do I have to include a narrative stating that the credit will be submitted in the v4 version? or how can I specify that this credit will be in the new version V4?

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 30 2014 LEEDuser Expert 14731 Thumbs Up

You can read the V4 credit language here.
http://www.leeduser.com/credit/NC-v4/SSc6#lang-tab

There are no interior lighting requirements.

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners Jun 30 2014 Guest 1395 Thumbs Up

Rosemaria,

you can download the interactive pdf of the LEED online submittal form for the v4 version of the credit in the LEED credit library. Fill that out and then make a pdf of it and upload it in LEED Online as a supporting document and put in a comment in LEED online that you are using the v4 version. Don't know if this is the right way, but it is what we have done.

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LEED Consultant Green Building and Alternative Energy Jul 02 2014 LEEDuser Member 1301 Thumbs Up

Thank you both, Bill and Glenn.

Regards!

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Stella Stella
Jun 20 2014
Guest
36 Thumbs Up

Actual exterior Lux reading

Can actual lighting level measurements be used as for compliance for this credit?

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 20 2014 LEEDuser Expert 14731 Thumbs Up

I've only seen actual measurements allowed for existing building.

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Stella Stella Jun 25 2014 Guest 36 Thumbs Up

Thanks Bill. We have a project which is a new development (LEED NC 2009) but there were some exterior luminaries installed some 20 years ago when the whole site and the other existing buildings were developed. Now some of these existing lamps fall within our LEED boundary for the new development. Do we need to perform exterior lighting simulation to show light trespass beyond the site boundary? If yes we don’t have the data for the existing lamps, so can we use a generic ELUMDAT file for those? Please advise. Thanks.

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 26 2014 LEEDuser Expert 14731 Thumbs Up

It sounds like you have something similar to a campus project. You may want to extend the "lighting boundary" to include the whole campus if it helps with your lighting calculation. But any of your existing fixtures within the "project boundary" will need to comply with this credit. Moving the lighting boundary out past the project boundary may make it easier to show that these existing fixtures are compliant. The uplight limits will be a challenge still for these existing fixtures. How many existing fixtures are inside the project boundary? Any appetite to replace just these 20 year old fixtures?

I can understand finding an IES file for this old fixture will be difficult. If you have a generic file or a similar product file it should be acceptable. Things can change a lot on a 20 year old fixtures. I see many that have a very yellow lens from years of UV exposure. I'm sure this has significantly changed the light output of the fixture. All we can due is make a reasonable effort and get as close as possible.

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Stella Stella Jun 26 2014 Guest 36 Thumbs Up

Thanks Bill. But is it possible to exclude those existing lamps since they weren’t installed as a part of this new development and analyse the only the newly installed ones?

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 27 2014 LEEDuser Expert 14731 Thumbs Up

Only if they are owned by the city for use by the city.

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ADRIENN GELESZ LEED AP ABUD Engineering Ltd.
Jun 19 2014
LEEDuser Member
960 Thumbs Up

Industrial site lighting

Hi all,

A question about industrial sites:
According to ASHRAE 90.1- section 9.4.5 Exterior Building Lighting Power, lighting used for the following exterior applications
is exempt when equipped with a control device
independent of the control of the nonexempt lighting:
g) Lighting for industrial production, material handling,
transportation sites, and associated storage areas.

Does this mean that the truck roads, loading dock shouldn't be included in the lighting calculation, nor in the energy model, if they have separate control? What about the illuminance values, can these lights also be excluded?
If they are not on a separate control, then what values can be used; for parking and drives? plazas?

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 19 2014 LEEDuser Expert 14731 Thumbs Up

truck roads does not fit any of the descriptions listed in exception "g".

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ADRIENN GELESZ LEED AP, ABUD Engineering Ltd. Jun 19 2014 LEEDuser Member 960 Thumbs Up

it's material transportation - it was not quite clear. But what about loading docks?

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 20 2014 LEEDuser Expert 14731 Thumbs Up

Any road can be used for material transportation. I don't think it makes a difference.

Loading docks might be a bit of a gray area. If a building is like a Walmart with loading docks for product delivery I'd be hesitant to claim this exception. But if the building is a large distribution warehouse with dozens of loading docks I would use the exception. I think scale is important.

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Deborah Zimmerman Michaud Cooley Erickson
Jun 19 2014
Guest
32 Thumbs Up

Campus lighting calcs at project/lighting boundary

Our project is a new building being built on an existing campus. We have lights near one edge of the project/lighting boundary; this is NOT the property line as the campus is on the other side of the project/lighting boundary. The entire campus is considered to be an LZ2. Are light levels on the other side of this boundary an issue? I'd appreciate any input you could give; thanks!

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James Weingarten Electrical Designer, MEP Associates Jun 19 2014 Guest 119 Thumbs Up

Take a look at credit interpretation 10114.

http://www.usgbc.org/leed-interpretations?keys=10114&=Search#

Sounds like you have a very similar situation.

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners Jun 19 2014 Guest 1395 Thumbs Up

Better yet, just use the new LEED v4 version of the credit. It's easier to deal with in many respects. You can use it on LEED-2009 projects. Trespass calculations are made at the Lighting Boundary. Lighting Boundary can be moved out to contain all contiguous properties owned by the same owner that are the same or higher lighting zone designation. Sounds like you can move the Lighting Boundary out the the extents of the whole campus. Note that only the exterior fixtures within the LEED Project Boundary are counted in the calculations.

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Deborah Zimmerman Michaud Cooley Erickson Jun 19 2014 Guest 32 Thumbs Up

Can I chose where to place the lighting boundary on the campus or does it then need to include the entire campus? This is a huge campus and I won't have to extend far to meet the illumination requirements.

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners Jun 19 2014 Guest 1395 Thumbs Up

Well, that's an interesting question. I suppose you could put the Lighting Boundary in some arbitrary location far enough out that you meet the limits. I guess I'd suggest you try to do it in as logical a way as possible and include some notes to explain what you are doing. You don't want to confuse the reviewer. Another approach (and the one I imagine I would take) would be to explain in a narrative that the Lighting Boundary is so far away from the project site (1000's of ft. or whatever) that it is effectively irrelevant. I'd then include an overall campus map with the Lighting Boundary drawn.

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Deborah Zimmerman Michaud Cooley Erickson Jun 19 2014 Guest 32 Thumbs Up

Glenn, I like your option much better! Thank you. I will try that approach.

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Jason Cocek
Jun 18 2014
Guest
100 Thumbs Up

EBOM Compliance Path

Does anyone know if the Exterior Lighting Option 3 under the EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. Rating System (nighttime illumination measurements) can be used as an alternative compliance path for the exterior portion of the NC Credit?

Thanks!

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Bill Swanson PE, LEED AP, Integrated Architecture Jul 21 2014 LEEDuser Expert 14731 Thumbs Up

I'm pretty sure that new construction projects have to comply with the wording in the NC version of the credit.

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Cristina Algaze Architect. LEED AP BD+C.
May 25 2014
LEEDuser Member
80 Thumbs Up

Lighting in a plant nursery with no opaque surfaces

I have a plant nursery that is enclosed with Saran material (translucent). It has lighting that is connected to a timer switch that assures that it will be off at night time. No operations are expected at night. Nonetheless, the lighting could be interpreted as exterior lighting because of the opened nature of the plant nursery (it has no opaque surfaces anywhere). Does this lighting has to comply with no lumens above 90 degrees nadir as well? Thanks

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 05 2014 LEEDuser Expert 14731 Thumbs Up

My first question is why do you have lighting if the roof of the nursery is translucent and you want it dark at night?

LEED has typically defined the boundary between inside and outside as the water vapor barrier for other credits like the VOC credit.

I looked up ID#5313 made on 05/27/2008 and they consider lights for the plants as a process load and that lighting for people should be part of the interior lighting calculation.

I would consider this an interior lighting application and the same restrictions would apply to any building with a skylight and plants below. If you state in your write-up that controls will keep the lights off from 11pm-5am then it should be compliant.

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Lyle Axelarris Civil/Structural Engineer, LEED AP BD+C, O+M, Design Alaska Jun 05 2014 LEEDuser Member 557 Thumbs Up

Not to stray from the point, and with all due respect to you, Bill, but the Building Science nerd in me has to point out that VOC boundary for IEQc4.x is the "weatherproofing system" (often taken as the water resistive barrier), which is often different than the vapor control layer. In my climate, there may be 2 feet of insulation between these two layers. Why the WRB is chosen as the inside/outside boundary instead of the air barrier is an entirely different rant of which I will spare you. Sorry to nit-pick... must just be feeling chatty :)

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Bill Swanson PE, LEED AP, Integrated Architecture Jun 06 2014 LEEDuser Expert 14731 Thumbs Up

Lyle, A "weatherproofing system" can be several inches thick and has lots of gray area. A "weatherproofing membrane" is thin. The siding and roofing materials are part of the "system" but are outside of the "membrane" and considered outside of the building. Any part of the system that is inside of the membrane is treated as inside of the building. This is the Interpretation I was referring to for the VOC credit.

ID#5955 made on 06/21/2004
Prerequisite/Credit: EQc4.1 - Low-emitting materials - adhesives and sealantsA sealant has adhesive properties and is formulated primarily to fill, seal, or waterproof gaps or joints between 2 surfaces. Sealants include sealant primers and caulks. (SCAQMD Rule 1168. )Sealants are used on wood, fabric, paper, corrugated paperboard, plastic foam and other materials with tiny openings, often microscopic, that may absorb or discharge gas or fluid. Rating System: LEED BD+C: New Construction

Inquiry
This is a USGBC administrative CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide to define the term indoor in the credits Intent section, thus clarifying the scope of the credit.

Ruling
Essentially, if a product is inside the exterior moisture protection it is a controlled product (it must comply with the credit requirement). To elaborate: all materials that emit contaminants that have the potential to enter the indoor air will be considered as indoor sources of contaminants. Materials which have the potential to communicate their emissions to the indoor air include all indoor surfaces in contact with the indoor air including flooring; walls; ceilings; interior furnishings; suspended ceiling systems and the materials above those suspended ceilings; all ventilation system components in communication with the ventilation supply or return air; and all materials inside of wall cavities, ceiling cavities, floor cavities, or horizontal or vertical chases. As an example these materials include the caulking materials for windows, and insulation in ceilings or walls. Examples of materials that have little or no potential for communicating with the indoor air are those siding and roofing materials that are on the exterior side of the waterproofing membrane. Applicable internationally.

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Lyle Axelarris Civil/Structural Engineer, LEED AP BD+C, O+M, Design Alaska Jun 06 2014 LEEDuser Member 557 Thumbs Up

Agreed. But I still contend that vapor control layer is different than the water control layer, and I still think that USGBC has it wrong here - boundary between indoor air and outdoor air is at air barrier, not "waterproofing membrane". In many climates and enclosure designs, these are the same thing, but this is not always the case. The air barrier system is what resists infiltration/exfiltrationExfiltration is air leakage through cracks and interstices and through the ceilings, floors, and walls. (and hence airborne contaminant transport through the assembly), which is driven by differential pressure; whereas, the water barrier resists liquid water intrusion, which is driven by gravity and capillary action. Vapor retarder layer resists vapor diffusion, which is driven by differential vapor pressures, and thermal barrier resists heat transfer, driven by differential temperatures.
The four control layers are: water, thermal, air, and vapor. Each of these serve different purposes, are subjected to different loads, and may or may not consist of different materials in different locations within the enclosure assembly. The confusion between these barriers/control layers has frustrated building scientists for decades, so I suppose I shouldn't be surprised that LEED displays the same confusion (but I still wish that Lstiburek, Straube, Yost, etc. would be on IEQ TAGLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system.).
When the air barrier is interior of the weather resistant barrier, how are the thermal barrier materials in between the two "communicating with the indoor air"? I am in strong support of low-VOC everything, and yes there are, in reality, small leaks in even the tightest building which could bring cavity contaminants into the indoor air, but I think it is important to know that this is not resolved by waterproofing - it is resolved by air sealing. A well-installed air barrier on the interior of the wall cavity will perform better than a non-continuous "waterproofing membrane" on a building with no other air barrier (with regards to preventing VOC migration from building enclosure materials into the occupied space). Air pressure control is the key here, not gravity or capillarity.
I understand that the WRB is a conservative layer to choose for pollutant control, but it is technically incorrect, and it undermines the important role that the air barrier plays in IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors., as well as the importance of barrier continuity. What do you do for buildings with no “weatherproofing membrane”? In dry climates, SIPs with face-sealed siding or assemblies that have continuous, exposed concrete on the exterior are examples of enclosures that do not have waterproofing membranes but, if properly designed and installed, could have very good air barriers that would prevent VOC migration from non-interior-surface enclosure assembly materials.
I guess I didn’t spare you my rant :). And sorry, Christina – I didn't mean to hijack your thread.

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Magda Aghababyan CEO Co-Energi (Pvt) Ltd.
May 19 2014
LEEDuser Member
479 Thumbs Up

ACP for light pollution reduction

Dear all,

In a situation where there are some spot lamps for emergency maintenance that can emit upward lights but used only for max. 2 - 3 hours a month, is it possible to use a weighted averaged calculation for upward light emmittance to show compliance?

Please share your thoughts on this.

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners May 19 2014 Guest 1395 Thumbs Up

No, you can't do a weighted average. You could try writing a narrative explaining this special situation and claim that these fixtures should be excluded.

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Michael Johnson Architect Chenevert Architects
May 16 2014
LEEDuser Member
670 Thumbs Up

light trespass along major city streets

We have a project along a major city street. the city street lights are very bright. I understand these are not included in the photometric calculations, but it causes a rather ridiculous scenario in which light trespass from project must be .01 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. 15' away from site boundary - when in reality - 15' from site boundary (along this road) is something far far over that.

is there no interpretation to account for this?

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners May 16 2014 Guest 1395 Thumbs Up

Michael,

There is an interpretation that allows you to go out to the centrerline of the roadway. But you should really just use the LEED v4 version of this credit (which you are allowed to do for LEED-2009 projects). This interpretation is baked into the v4 version, along with many other improvements which make the credit easier to use.
http://www.usgbc.org/node/2600382?return=/credits/new-construction/v4/su...

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Crista Shopis Senior Engineer, LEED AP Taitem Engineering
May 08 2014
LEEDuser Member
78 Thumbs Up

No glazing in the building shell

can a building still achieve this credit if they adhere to ASHRAE 90.1 for exterior lighting, none of the exterior lighting falls over the site boundary and there is no glazing in the building shellThe exterior walls, roof, and lowest floor of a building, which serve to separate and protect the interior from the elements (precipitation, sunlight, wind, temperature variations).?

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Bill Swanson PE, LEED AP, Integrated Architecture May 08 2014 LEEDuser Expert 14731 Thumbs Up

Yes and no.

The project has to comply with Addendum i of ASHRAE 90.1-2007.
and
Limit interior light from spilling out thru the windows.
and.
Limit exterior light from spilling onto the neighbors property.
and
Limit exterior light from shining up into the sky messing with wildlife.

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Lawrence Lile Chief Engineer Lile Engineering LLC
Apr 14 2014
LEEDuser Member
1316 Thumbs Up

LZ1 vs LZ2 vs LZ3

We are working on a maintenance facility for a landfill (Don't worry - there is a big compost and container recycling operation there too!) They will be operating and maintaining garbage trucks. Normally I'd want to say this is LZ3 (commercial/industrial). However the landfill is located in the middle of a 600 acre site in a rural area. This makes me lean toward LZ1, the most restrictive category for site lighting.

How would you expect a LEED reviewer to call this one?

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Bill Swanson PE, LEED AP, Integrated Architecture Apr 15 2014 LEEDuser Expert 14731 Thumbs Up

I've long complained that the lighting zone definitions are vague. That you are debating between LZ1 and LZ3 is sad. Things should not be this confusing. I don't know how a LEED reviewer would call this. Most of the time they seem to defer to the submitter's opinion but they have been known to disagree.

If there is a single building I would lean toward LZ1. If there is a complex of several buildings with activity outside most of the night I would lean towards LZ3 just around the buildings and then at some distance draw a line and say everything past this line is LZ1. Very arbitrary. If you can split the difference try submitting at LZ2.

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Anne Harney Senior Associate Ayers Saint Gross Architects + Planners
Mar 11 2014
LEEDuser Member
326 Thumbs Up

BUG Rating for Full-Cutoff Compliance

An exception is noted in the above requirements "If locally mandated lighting is higher than ASHRAE, you can still get the credit if you use full cutoffA full cutoff luminaire has zero candela intensity at an angle of 90 degrees above the vertical axis (nadir or straight down) and at all angles greater than 90 degrees from straight down. Additionally, the candela per 1,000 lamp lumens does not numerically exceed 100 (10%) at an angle of 80 degrees above nadir. This applies to all lateral angles around the luminaire. fixtures and make your case well". How does a fixture's BUG Rating compare to ASHRAE 90.1-2007 requirements for the project zone per IESNA RP-33.

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Bill Swanson PE, LEED AP, Integrated Architecture Mar 11 2014 LEEDuser Expert 14731 Thumbs Up

Your wording is a little confusing. Are you trying to quote from the Checklist tab under Design Development?

What are you trying to do for your project?

BUG rating has nothing to do with this version of the credit. You may use the v4 credit language if you want to use the BUG rating.

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Anne Harney Senior Associate, Ayers Saint Gross Architects + Planners Mar 11 2014 LEEDuser Member 326 Thumbs Up

Currently, our State Law prohibits the use of State funds to install or replace a permanent outdoor luminaire for lighting on the grounds of any State building or facility, unless, for a luminaire with an output of more than 1,800 lumens, the luminaire is a restricted uplight luminaire (allows no direct light emission above a horizontal plane through the luminaire’s lowest light-emitting part).

We have a bill being considered in current legislative session that introduces a BUG rating option as opposed to the full cutoffA full cutoff luminaire has zero candela intensity at an angle of 90 degrees above the vertical axis (nadir or straight down) and at all angles greater than 90 degrees from straight down. Additionally, the candela per 1,000 lamp lumens does not numerically exceed 100 (10%) at an angle of 80 degrees above nadir. This applies to all lateral angles around the luminaire. fixture requirement, mandated for state funded projects replacing more than 25% of existing fixtures.

Our project is a public University with a LEED Gold Certification goal. Our LEED site boundary includes existing site lighting which will need to be replaced, as well as a new proposed site lighting plan. LEEDv2009 NC dictates site lighting selection is a full-cutoff fixture. But it may be best for the University to select a fixture that meets the BUG requirements. I see BUG is an option in v4. Is that in lieu of the calculation method?

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners Mar 12 2014 Guest 1395 Thumbs Up

Anne,

Can you tell me what State you are in? I'm very interested in state level light pollution control legislation.

Per USGBC, the v4 version of the credit can be used now on LEED-2009 projects. The v4 version allows you to use the BUG method to meet the Uplight limits and/or to meet the Trespass limits. Read the credit language carefully, the requirements are pretty clear.

I do not believe that LEED-2009 NC SS8 "dictates site lighting selection is a full-cutoff fixture". It just limits the amount of light above horizontal and the amount of light at the boundary. Where do you see that requirement?

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Bill Swanson PE, LEED AP, Integrated Architecture Mar 12 2014 LEEDuser Expert 14731 Thumbs Up

State law trumps LEED. If you comply with the current law it sounds like your uplight won't be an issue. Will your project be done by the time the proposed bill becomes an enforced law?

As Glenn mentioned there is nothing in v2009 that requires full-cutoff fixtures. But the total site limit for uplight is very low.

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Anne Harney Senior Associate, Ayers Saint Gross Architects + Planners Mar 12 2014 LEEDuser Member 326 Thumbs Up

Maryland State Law 14-412

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Bill Swanson PE, LEED AP, Integrated Architecture Mar 17 2014 LEEDuser Expert 14731 Thumbs Up

Weird, there are two laws with the same identification.

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Saud Abdul Rasheed LEED Engineer Al Yamama Company
Mar 03 2014
LEEDuser Member
184 Thumbs Up

Exterior Lighitng: Facade Lighting

Hello All,
My question may be simple but still I want to be clear about it. When we are calculating the exterior lighting, in LEED Reference Guide as well as ASHRAE 90.1 2007 we have the units either as "watts per linear foot/metet" or "watts per square feet/square meter"?. For example in the latest addendum of the ligthing credit in SS it says for LZ2 the LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. for Facade lighting is 0.1W/ft2 or 2.5W/linear meter. How can I calculate these do I need all the Facade area for both calculations? and how I can convert from linear meters to square meters or vice verse?

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Gustavo De las Heras Izquierdo Arch. Eng. LEED AP BD+C; O+M, Revitaliza Consultores Mar 03 2014 Guest 186 Thumbs Up

In my opinion:
-Area: you have to measure the facade area in the elevation drawing.
-Linear: you have to measure the length of the facade (floor plan)

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Saud Abdul Rasheed LEED Engineer, Al Yamama Company Mar 03 2014 LEEDuser Member 184 Thumbs Up

Thanks Gustavo.

- Do I measure all the facade area and then distribute lighting in the area so that total Watts per meter square does not exceed the total LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. limit for the whole area?

- For linear calculation I am not sure how to do it. If i only measure the length I will still be having width of the facade so depending on this I may be installing lights on the length from two sides of the width or even three lines of lighting along the length of facade depending on the width.

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S S Mar 03 2014 Guest 115 Thumbs Up

The above said opinion is correct. Further no need to convert from linear meters to square meters or vice verse.If the light fittings are located to illuminate the whole façades, then you need to calculate watts per square meters method otherwise you can go with watts per linear meters method.

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Saud Abdul Rasheed LEED Engineer, Al Yamama Company Mar 04 2014 LEEDuser Member 184 Thumbs Up

Thank you!

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Rustem Saitov Aug 04 2014 Guest 7 Thumbs Up

Saud,
I have spend quite some time trying to figure out the very same issue.
Based on my findings I believe that the calculations should be done "for each illuminated wall or surface", and the compliance should be demostrated "for each illuminated wall or surface" separately.
Basically, that means that you have to get the dimensions of every illuminated wall or surface unit, and show that it is compliant. As stated in ASHRAE 90.1-2007: "LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. calculations for the following applications can be used only the specific application and cannot be traded between surfaces or with other exterior lighting..".
Depending on a naute of your project, you can significantly underestimate your LPD in case you use total area of facade and divide it on total lighting power.
Anyway, I hope it is not too late for amendments in your project.

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners Aug 04 2014 Guest 1395 Thumbs Up

You need to look at ASHRAE/IES INTERPRETATION IC 90.1-2007-20
http://www.techstreet.com/products/1853857
if this link doesn't work just google it.

"The allowance for each facade may be calculated by applying the watts
per square foot value to the facade area, regardless of the distribution of illumination on that facade area."
("facade area" is a defined term in the standard)

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Rustem Saitov Aug 05 2014 Guest 7 Thumbs Up

But then you may look at LEED 2009 the Missing Manual
http://www.scribd.com/doc/193875375/LEED-2009-the-Missing-Manual#page=2
"To calculate building façade lighting power density, how do you determine the area used in the calculation?
Use only the area that has measurable light on the surface; baseline and proposed are the same".

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners Aug 07 2014 Guest 1395 Thumbs Up

Rustem,

90.1-2007 is the referenced standard in LEED-2009. The official 90.1 interpretation determines how the standard is applied.

The interpretation was issued specifically because of the misunderstanding that many of us had, as expressed in the "Missing Manual"

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Rustem Saitov Aug 08 2014 Guest 7 Thumbs Up

Glenn,
OK, great, thank you for the clarification.

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James Weingarten Electrical Designer MEP Associates
Feb 27 2014
Guest
119 Thumbs Up

Interior Shut off vs Safety

In version 2009, I have to shutoff or reduce interior lighting. The interior space is a chiller plant where lighting shutoff or reduction would create a safety risk. Ashrae allows me to "exempt" these areas from automatic shutoff controls. Does LEED as well? Or would I be required to provide shades on windows between 11 and 5?

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners Feb 27 2014 Guest 1395 Thumbs Up

James,
I don't think they'd allow that exemption, but remember that you are allowed "after hours override".

Are you aware that there are no interior lighting requirements in the v4 version of this credit and that you can now use the LEED v4 version of this credit on LEED-2009 projects.
http://www.usgbc.org/node/2600382?return=/credits/new-construction/v4/su...
http://www.usgbc.org/articles/use-v4-credits-your-v2009-project?utm_sour...

If you can meet the 2009 requirements you'll very likely meet the v4 requirements. In general the credit is less complicated and easier to use.

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Donald Green Project Manager Sustainable Design Consulting, LLC
Feb 26 2014
LEEDuser Member
805 Thumbs Up

Event Center

Is there any exception to a project that would only be used 12 times a year (1 time per month) past the 11pm time line for interior lighting levels? The project would otherwise meet the requirements for the 50% cut off the other 353 days of the year. The project would be in LZ4 and surrounded by other like uses that typically would be closed at that hour anyways.

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Glenn Heinmiller IALD, LC, LEED AP, Principal, Lam Partners Feb 26 2014 Guest 1395 Thumbs Up

Donald,
There are no interior lighting requirements in the v4 version of this credit.
You can now use the LEED v4 version of this credit on LEED-2009 projects.
http://www.usgbc.org/node/2600382?return=/credits/new-construction/v4/su...
http://www.usgbc.org/articles/use-v4-credits-your-v2009-project?utm_sour...

If you can meet the 2009 requirements you'll likely meet the v4 requirements. In general the credit is less complicated and easier to use.

You should also be careful about claiming LZ4. Unless you are in Times Square NYC or Las Vegas Strip or something like it, you may be questioned by the reviewer.

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Donald Green Project Manager, Sustainable Design Consulting, LLC Feb 27 2014 LEEDuser Member 805 Thumbs Up

Thanks for the information, I guess downtown Richmond, VA isn't quite NYC... so I guess we will look into LZ3.

Thank you,

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Bill Swanson PE, LEED AP, Integrated Architecture Feb 27 2014 LEEDuser Expert 14731 Thumbs Up

On a different credit I was told once by a reviewer that a board room that was occupied once a month was considered "regularly occupied" and therefore must comply with the credit requirements. Assume all rooms must comply with this credit. Rarely used doesn't seem to be a justification they accept.

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Jens Apel
Feb 11 2014
LEEDuser Member
876 Thumbs Up

Hotel guest rooms = dwelling units

I understand that residential units are exempt from interior lighting requirements. Does this include hotel guest rooms as well?

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Aug 21 2014
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